Potential-step electrodeposition

Although the mechanisms discussed above are still topics of debate, it is now firmly established that the electrodeposition of conducting polymers proceeds via some kind of nucleation and phase-growth mechanism, akin to the electrodeposition of metals.56,72-74 Both cyclic voltammetry and potential step techniques have been widely used to investigate these processes, and the electrochemical observations have been supported by various types of spectroscopy62,75-78 and microscopy.78-80... 

In searching to formulate a mechanism of CuInSc2 phase formation by one-step electrodeposition from acid (pH 1-3) aqueous solutions containing millimolar concentrations of selenous acid and indium and copper sulfates, Kois et al. [178] considered a number of consecutive reactions involving the formation of Se, CuSe, and Cu2Se phases as a pre-requisite for the formation of CIS (Table 3.2). Thermodynamic and kinetic analyses on this basis were used to calculate a potential-pH diagram (Fig. 3.10) for the aqueous Cu+In-i-Se system and construct a distribution diagram of the final products in terms of deposition potential and composition ratio of Se(lV)/Cu(ll) in solution. 

The Au-NPs were electrodeposited on the carbon fiber microelectrodes from 0.5 M H2S04 solution containing l.OmM Na AuCl4] by applying a potential step from 1.1 V to 0V for 30 s. Cysteine-modified Au-NPs-electrodeposited CFMEs were prepared by... 

Fig. 19. Sampled-current voltammogram constructed from the current-time transients that resulted from a series of potential-step experiments at a stationary Pt electrode in a 35.0 x 10 3 mol L-1 solution of Ni(II) in the 66.7 m/o AlCl3-EtMeImCl melt ( ) total current, ( ) partial current for the electrodeposition of Ni, (O) partial current for the electrodeposition of Al. The total current was sampled at 3 s after the application of each potential pulse. Adapted from Pitner et al. [47] by permission of The Electrochemical Society. 

A series of papers have been devoted to the silver deposition on single-crystal surfaces of other metals, mainly Au(lll) and Au(lOO). Zell etal. [303] have performed electrochemical in situ STM, cyclic voltam-metric, and potential-step studies of phase formation during Ag (and Al) electrodeposition from the room-temperature molten... 

Fig. 4.8 Square-wave voltammograms of graphite-polyester composite electrodes modified by cobalt blue (a,c), and glazed ceramic sample from Valencia, Spain (b,d), immersed into 0.10 M HCl. (a,b) Potential scan initiated at 4-0.65 V in the negative direction (c,d) potential scan initiated at —1.05 V in the positive direction after an electrodeposition step of 60 s at —1.05 V. Potential step increment 4 mV, square-wave amplitude 25 mV, frequency 15Hz[231]...

Fig. 4.13 Square-wave voltammograms of PIGEs modified with mixtures of a zirconium-containing sample plus Zr02 (standard) and ZnO (auxiliary reference material) in contact with O.IOM VaCZ. Sample ZnO mass ratio equal to 4.422 ZnO Zr02 mass ratio equal to (a) 0.163 (b) 1.216 and (c) 5.374. Potential scan initiated at —1.45 V in the positive direction without prior electrodeposition step. Potential step increment 4 mV square-wave amplitude 25 mV frequency 15 Hz. [234]...

Fig. 4.18 Stripping oxidation peaks recorded for (a) Sn02 plus auxiliary clay (50%, 50% w/w mixture), and (b) Sn02 plus PbCOs plus auxiliary clay (20%, 40%, 40% w/w mixture) specimens attached to PlGEs in contact with 0.50 M acetate buffer. Square-wave voltammograms initiated at — 1.05 V after an electrodeposition step of 30 s at that potential. Potential step increment 4 mV square-wave amplitude 25 mV frequency 15 Hz [242]...

Figure 7.7 Copper crystals electrodeposited on PEDOT layers by means of single-potential-step experiments (a, c) and double-potential-step experiments involving copper stabilization (b, d) before (a, b) and after (c, d) UV-irradiation of the CP surface. (Micrographs a and b adapted with permission from M. Hieva, V. Tsakova, N.K. Vuchkov, K.A. Temelkov, N.V. Sabotinov, UV copper ion laser treatment of poly-3,4- ethylenedioxythiophene,. Optoelectron. Adv. Mat., 9, 303-306 (2007). Copyright 2007 Nartional Institute of Research and Development for Optoelectronics.)...

Fig. 16.2 CVs obtained for the O2 reduction at Au nanoparticle-deposited Au electrodes in O2-saturated 0.5 M H2SO4. A potential step from 1.1 to 0 V was used for the electrodeposition of Au particles from 0.5 M H2SO4 solution containing 0.11 mM Na[AuCl]4 with deposition time of (a) 5 s and (b) 10 s. Potential scan rate = 100 mV s ...

El-Deab studied the influence of the electrodeposition time on the crystallographic orientation of Au nanoparticles electrodeposited on glassy carbon prepared by potential step electrolysis and on their electrocatalytic properties toward ORR in alkaline medium (0.5 M KOH) [73]. He observed that particles prepared in short time (5-60 s) had smaller size (10-50 nm) and showed a higher particle density (number of particles per unit area), as revealed by SEM images, than those prepared... 

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